Cream together the butter and sugars, stir in egg and vanilla. Now mix in flour, baking powder and salt until just combined. The batter should be crumbly and you will probably need to use your (clean) hands to combine it a bit more to form a dough ball. Cover in plastic wrap and place in the freezer for 20 minutes.

Now form into small round disks, about 2-3 inches in diameter and uniformly thick. You want your cookies to all sort of match each other in size because you will be placing one of top of another to form sandwich cookies. Bake at 350 F for 15-18 minutes, allow to cool completely on a cooling rack before adding filling. Once cool, spoon a couple of tablespoons of Nutella on one cookie and place another on top. Devour, and don't apologize.

Ah this looks so delicious! Never actually thought of doing this actually.

Re th drawing for your blog- I am at the moment unfortunately (and fortunately!) in a full time job in finance and working on some projects on the side so I cannot help you ATM. Perhaps in a couple of months when things have calmed down though! I'm really really honoured that you shoul ask :)